put somebody/be at a disadvantage
be at a disadvantage
To be in an unfavorable position in comparison to others. They knew for weeks, but I'm just getting all of this information now—I'm at a disadvantage here. You'll be at a disadvantage playing against a player as skilled as Katie.
See also: disadvantage
put (one) at a disadvantage
To put someone in an unfavorable or uncompetitive position compared to others. John knew about the deal for weeks, but I'm just getting all of this information now—he's putting me at a disadvantage here! She was put at an immediate disadvantage playing against the top seeded tennis player in the first round of the tournament.